, and motivations behind, many loft conversions is that they can significantly increase the value of your home. Should you decide to sell your property the prospective buyer's surveyor will check on the permissions for the conversion, and its compliance with the relevant regulations. It's therefore not worth cutting corners or taking chances. Do the job properly using professional builders/architects. This is the best piece of advice I can offer you. The additional cost of using professionals is offset by the peace of mind you will receive knowing that the job has been properly, to a high standard, and will stand up to the scrutiny of any surveyor.